Optical hair removal devices provide high-energy laser beams with wavelengths absorbable at hair roots, at pulses having durations usually within a range between 1 ms and 500 ms (ms: milliseconds). Upon being subjected to laser beams, hair roots get heated and thus damaged. Permanent depilation can be achieved by several repetitions of such application.
WO 2005/102 201 A1 describes a hair removal device aiming for a certain distance between skin and a contact plate for obtainment a reliable hair removing of locally curved regions of skin.
US 2006/0 095 099 A1 describes a stand-alone laser device comprising a support structure enabling a patient to be scanned without moving the laser energy source.
EP 1 031 324 A1 describes a laser depilation apparatus for alleviating damage to surrounding tissues of treated hair follicles.
TR 2012/13577 describes a laser hair removal device aiming for precise hair removal notwithstanding the optical contrast around target hair.
Some of the main problems encountered in known laser hair removal technology can be summarized as follows:                In order to obtain an efficient hair removal by selective damaging of hair roots, target hair root shall absorb more light in comparison with surrounding skin regions. But the light absorbing pigment melanin is present in hair roots and also in skin. Therefore in low-contrast color combination cases of pale skin with light hair, or dark skin with dark hair, sufficient optical contrast for selective damaging of hair cannot be easily achieved. As a result, even maximum values of light energy provided onto hairy skin cannot damage target hair without damaging the surrounding skin as well; and either permanent hair removal cannot be achieved, or a large number of sessions is required for permanent hair removal.        Hair removal necessitates heating of target hair root to a threshold temperature for permanent damage thereof. Below such temperature, heating provokes repair mechanisms thus the target hair root builds up instead of getting damaged. In cases of above-mentioned low-contrast color combinations, or similarly, in skin regions where relatively thick and thin hair roots are present in a mixed manner such as at the face of a patient, thin hair builds up due to said mechanism; and this phenomenon is referred to as ‘paradoxial hypertrichosis’.        Especially patients having darker colored skin experience widespread sharp aches on their skin around laser-treated areas thereof. This presumably occurs due to high absorbance of light energy by high concentration of melanin in dark skin.        In cases where the amount of light energy per unit area (i.e. fluence) is arranged and calculated imprecisely and improperly, the risk of ambustion arises at wide skin portions.        